Field of Disclosure
Embodiments described herein generally relate to improving energy efficiency of a photovoltaic system. Specifically, a photovoltaic system and a method of operation thereof is provided that resolve solar light into various color components and absorb the resolved colors into different materials optimized for those color bands.
Description of the Related Art
The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Solar energy proves to be a good source of natural energy from which electrical energy can be obtained via a photovoltaic system. Typically, a photovoltaic system includes a solar cell (also called a photovoltaic cell) that is an electrical device that converts the energy of light directly into electricity. Typical photovoltaic systems may achieve high energy conversion efficiency by incorporating an array of expensive solar cells such as multi-junction solar cells. To reduce the cost overhead incurred in constructing such a system, the photovoltaic system may include low-cost solar cells. However, the overall efficiency of such a photovoltaic system is low, and typically unacceptable in various applications.
An optically concentrated photovoltaic system (CPV) can reduce costs of solar cells by focusing the incoming light on a smaller area of photovoltaic material. In an effort to improve the energy conversion performance of a photovoltaic system, multi-junction solar cells can be used that achieve an overall efficiency exceeding 40%. Multi-junction solar cells are solar cells with multiple p-n junctions made of different semiconductor materials. Each material's p-n junction will produce an electric current in response to a different range of wavelength of sunlight. A multi junction solar cell produces electric current at multiple wavelengths of light, and allows the minimization of the energy losses via thermalization process of the photo-generated carriers, thereby increasing the energy conversion efficiency of this device. However, the construction of such a multi junction solar cell is complex/costly, as multiple solar cells need to be stacked one on top of each other. Specifically, the fabrication process of a multi junction solar cell is complex because the crystalline structures of the different semi-conductor materials used in the stacked layers of the multi junction cell need to be matched. Furthermore, multi junction solar cells also face the problem of providing cooling to the stack of vertically mounted solar cells. In addition, the vertically stacked cells must produce the same current (current matching) which compromises the achievable efficiency. Accordingly there is a requirement for an improved photovoltaic system that achieves high efficiency in terms of energy conversion, whilst keeping the system cost low.